The following is a basic test of how different oxidizers affect sound and
thrust in whistle rocket motors. Equipment and rocket motors similar to the
ones used in the catalyst tests (here) were
used in this experiment.

First Series of Tests

The following is a basic test of how different oxidizers affect sound
and thrust in whistle rocket motors.

The four perchlorates tested were Firefox domestic ground perchlorate
(standard purity - sort of an off-white/light yellow color), some good
Taiwanese from another source, Firefox chunk domestic and high purity
Chinese from Skylighter. At the moment, the exact purity of each
perchlorate is unknown.

The fuel for all tests was finely milled Potassium Benzoate. The
catalyst for all tests was iron oxide. The ratio was 76/23/1 +3
mineral oil

Follow -on Tests

(aka - I need to get a life)

The following tests take into account the granularity of the perchlorate.
Specifically, the perchlorates in all tests were reduced to -325 mesh.
That is, the perchlorate powder was milled until it was less than 325 mesh.
Perchlorate may clump and mechanically bind when milled so the measurements
were done with a microscope. See pictures for examples of measurements. The fuel and catalyst
were changed from a
medium-low reacting combination (sodium benzoate and iron oxide) to a higher
reacting mix during the experiment because it was found that low reacting
fuels and catalysts tended to mask the strength of the potassium perchlorate
- essentially with some low power fuel/catalyst combinations, no discernable
difference could be seen between the perchlorates. Domestic perchlorate
showed nearly the same strength as Taiwanese.

The perchlorates tested were Firefox domestic ground perchlorate
(standard purity - sort of an off-white/light yellow color), some good
Taiwanese from another source, high purity
Chinese from Skylighter (also known as HP140), Spanish from Nitroparis (most
likely still Chinese), Swedish donated by Tim Seekon, Reagent grade from a
laboratory supply source, and cleaned domestic (recrystalized by Eric
Hunkins). At the moment, the stated manufacturer purities for the common
perchlorates are in doubt. The amount of impurities found in most commercial
perchlorates exceed the stated purities by several percent. (See perhloratenotesv2.pdf)

The Data

The third attempt follows in video format. The first
attempt showed differences but the perchlorates were not uniform in
granularity. The second attempt used a low power whistle mix and the thrusts
were hard to distinguish. This series use a high powered mix (as developed
in the whistle tests). While at first
glance, the third attempt seems to be a failure, it is not. These motors
survived hundreds of tests using unmodified perchlorates. Now, with the
perchlorates ground fine and a high powered catalyst/fuel mix, the results
are ... well.. pyrotechnic. Also, the cleaned domestic perchlorate
CATO'd while the normal domestic perchlorate did not. Take a look (wmv formatted movie):

After another failed run (run 4), it was decided to run all end-burners and no cores so that our
poor test stand wouldn't pop a cork. Here are the results of burns of two
increments (about 10 grams) of each perchlorate after it had been ball
milled for two hours in a 6" hobby ball mill, pressed to 6600 lbs in a
5/8" tube and fired on a small test stand.